Candana Yatra is a festival during the hot season in India in which the Deities are covered with sandalwood paste (candana) to cool them. (This is generally impractical in the West, where it is cold during this time.)
The 21 days festival begins on the day of Akshay Tritiya by all the marble deities being covered sandalwood paste. For the next three weeks, the small brass deities or “utsava murtis” are also covered in sandalwood paste every day.